Solve for $a$ : $26 = a + 27$
Explanation: Subtract $27$ from both sides: $ \begin{eqnarray} \\ \hphantom{26 {- 27}} &\hphantom{=}& \hphantom{a} \\ 26 &=& a + 27 \\ \\ {-27} && {-27} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ 26 {- 27} &=& a \\ \end{eqnarray} $ Simplify. $ a = -1$